(1) Field of the Invention
The invention relates to hydrogen peroxide (H2O2) engines and in particular to a novel hybrid rocket/turbine hydrogen peroxide based engine and hydrogen peroxide based propulsion system for micro air vehicle propulsion.
(2) Description of the Prior Art
Micro air vehicles (MAVs) play a key role in military and surveillance operations. For these MAVs, a range of engine characteristics is needed to meet specific requirements, such as low speed, low noise, high speed, etc. In this specification MAVs are defined as air vehicles which have a wingspan of 1 metre or less and/or a weight of 2 kg or less. Features such as weight, ease of starting, reliability, etc. are important in the choice of the power plant. Air breathing engines or motors are usually attractive on weight grounds because they do not have to carry their own oxidant. However this may not be so important at small scales when the mass of the engine itself is relatively high. In addition, of course, small engines have relatively poor thermal and propulsive efficiency due to low cycle temperatures.
Hydrogen peroxide engines are known. The inventors have determined that these engines can be built small enough and give adequate performance requirements for use in MAVs. Hydrogen peroxide can nowadays be generated xe2x80x98in the fieldxe2x80x99 by electrolytic techniques. It can be decomposed catalytically to produce steam and oxygen at high temperature and is an acceptable propellant in its own right with a high specific thrust and a low infrared (IR) signature.
The invention comprises a micro engine comprising a source of hydrogen peroxide and a source of hydrocarbon fuel; a decomposition region for decomposition of hydrogen peroxide and a combustion region for combustion of hydrocarbon fuel with oxygen produced from such decomposition; and a nozzle to exit products of such decomposition and combustion.
Further is provided a micro air vehicle equipped with such an engine and a method of propelling a micro air vehicle comprising the steps of decomposing hydrogen peroxide, combusting a hydrocarbon fuel with oxygen produced from such decomposition, and exiting products of such decomposition and combustion through a nozzle.
The invention also comprises a micro air vehicle having an engine having connection means to a tank adapted to contain hydrogen peroxide, a fuel tank connected to a region adapted to decompose hydrogen peroxide, a decomposition region/chamber suitable for decomposing hydrogen peroxide, a nozzle to accelerate the resulting decomposition products, a turbofan located downstream of the exit of said nozzle and located within a duct so as to provide propulsive thrust and means to provide a hydrocarbon fuel adapted to burn by consuming oxygen from the decomposition of hydrogen peroxide.